Electronic Transport Properties of Hot-Pressed B6Si

1987 ◽  
Vol 97 ◽  
Author(s):  
C. Wood ◽  
D. Emin ◽  
R. S. Feigelson ◽  
I. D. R. Mackinnon
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Electronic Transport ◽  
Hall Mobility ◽  
Anomalous Behavior ◽  
Nominal Composition ◽  
Electronic Transport Properties ◽  
Increasing Temperature ◽  
P Type

ABSTRACTMeasurements of the electrical conductivity, Seebeck coefficient and Hall mobility from -300 K to -1300 K have been carried out on multiphase hotpressed samples of the nominal composition B6Si. In all samples the conductivity and the p-type Seebeck coefficient both increase smoothly with increasing temperature. By themselves, these facts suggest small-polaronic hopping between inequivalent sites. The measured Hall mobilities are always low, but vary in sign. A possible explanation is offered for this anomalous behavior.

scholarly journals Synthesis and Characterization of Thermoelectric Co2XSn (X = Zr, Hf) Heusler Alloys

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 624
Author(s):  
Alessandro Difalco ◽  
Francesco Aversano ◽  
Stefano Boldrini ◽  
Alberto Ferrario ◽  
Marcello Baricco ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Curie Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Power Factor ◽  
Electronic Transport ◽  
Waste Heat ◽  
Heusler Alloys ◽  
Secondary Phases ◽  
Electronic Transport Properties

In this work, we report the results of an experimental investigation on the synthesis, structure, microstructure, mechanical, electrical conductivity, and Seebeck coefficient of Co2XSn (X = Zr, Hf) alloys. In both the alloys, the main constituent is a full Heusler-type compound that coexists with small amounts of secondary phases. Both alloys show a rather high Vickers hardness (around 900 HV) and an indentation fracture toughness typical of ceramics (around 2 MPa·m1/2). The electronic transport properties of the two alloys were measured for the first time. The temperature dependence of both the Seebeck coefficient and the electrical conductivity of the two alloys shows a change in correspondence of the Curie temperature. The Seebeck coefficient reaches a constant plateau, while the electrical conductivities show a transition from metallic to semiconductor behavior. As a consequence, almost constant values of the power factor have been obtained for the power factor above the Curie temperature, which is promising for an efficient exploitation of thermal gradients of several hundreds of degree in waste heat harvesting applications. Finally, on the basis of results from this work and from the literature, the effect of the substitution of the X element on the electronic transport properties in the series Co2XSn (X = Ti, Zr, Hf) is discussed.

scholarly journals Impact of Fermi Surface Shape Engineering on Calculated Electronic Transport Properties of Bi-Sb-Te

2021 ◽  
Vol 59 (1) ◽  
pp. 54-60
Author(s):  
Sang-il Kim ◽  
Jong-Chan Lim ◽  
Heesun Yang ◽  
Hyun-Sik Kim
Keyword(s):  
Electrical Conductivity ◽  
Fermi Surface ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Effective Mass ◽  
Power Factor ◽  
Electronic Transport ◽  
Surface Shape ◽  
Thermoelectric Performance ◽  
Electronic Transport Properties

Using thermoelectric refrigerators can address climate change because they do not utilize harmful greenhouse gases as refrigerants. To compete with current vapor compression cycle refrigerators, the thermoelectric performance of materials needs to be improved. However, improving thermoelectric performance is challenging because of the trade-off relationship between the Seebeck coefficient and electrical conductivity. Here, we demonstrate that decreasing conductivity effective mass by engineering the shape of the Fermi surface pocket (non-parabolicity factor) can decouple electrical conductivity from the Seebeck coefficient. The effect of engineering the non-parabolicity factor was shown by calculating the electronic transport properties of a state-of-the-art Bi-Sb-Te ingot via two-band model with varying non-parabolicity. The power factor (the product of the Seebeck coefficient squared and electrical conductivity) was calculated to be improved because of enhanced electrical conductivity, with an approximately constant Seebeck coefficient, using a non-parabolicity factor other than unity. Engineering the non-parabolicity factor to achieve lighter conductivity effective mass can improve the electronic transport properties of thermoelectric materials because it only improves electrical conductivity without decreasing the Seebeck coefficient (which is directly proportional to the band mass of a single Fermi surface pocket and not to the conductivity effective mass). Theoretically, it is demonstrated that a thermoelectric figure-of-merit <i>zT</i> higher than 1.3 can be achieved with a Bi-Sb-Te ingot if the non-parabolicity factor is engineered to be 0.2. Engineering the non-parabolicity factor is another effective band engineering approach, similar to band convergence, to achieve an effective improvement in power factor.

scholarly journals Влияние легирования ванадием на термоэлектрические свойства сплавов Гейслера Fe-=SUB=-2-=/SUB=-Ti-=SUB=-1-x-=/SUB=-V-=SUB=-x-=/SUB=-Sn

2019 ◽  
Vol 53 (6) ◽  
pp. 777
Author(s):  
А.И. Таранова ◽  
А.П. Новицкий ◽  
А.И. Воронин ◽  
С.В. Таскаев ◽  
В.В. Ховайло
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Experimental Study ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Thermoelectric Properties ◽  
Pristine Sample ◽  
Electrical Conductivity Behavior ◽  
P Type ◽  
Conductivity Behavior

In this work the results of an experimental study of Fe2Ti1-xVxSn alloys (x = 0; 0.06; 0.15; 0.2) are presented. According to the temperature dependencies of the electrical conductivity, Seebeck coefficient and thermal conductivity, it is established, that the studied compositions exhibit transport properties typical for semiconductors. The substitution of V at the Ti site leads to a change of the p-type electrical conductivity behavior to n-type; the pristine sample of Fe2TiSn has the best thermoelectric properties.

scholarly journals Structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1−x−yTixFeyO3−δ

2019 ◽  
Vol 21 (39) ◽  
pp. 21824-21835 ◽  
Author(s):  
Rian Ruhl ◽  
Jia Song ◽  
Vincent Thoréton ◽  
Sathya Prakash Singh ◽  
Kjell Wiik ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Transport Properties ◽  
Oxygen Transport ◽  
Electronic Transport ◽  
Structural Changes ◽  
Electronic Transport Properties ◽  
Perovskite Type

Correlating ionic and electronic transport properties with structural changes in perovskite-type oxides CaMn1−x−yTixFeyO3−δ (CMTF).

Electronic Transport Properties of Tin-Filled Cobalt Antimonides

2007 ◽  
Vol 26-28 ◽  
pp. 891-894
Author(s):  
Jae Yong Jung ◽  
Soon Chul Ur ◽  
Il Ho Kim
Keyword(s):  
Heat Treatment ◽  
Transport Properties ◽  
Electronic Transport ◽  
Single Phase ◽  
Induction Melting ◽  
Isothermal Heat Treatment ◽  
Degenerate Semiconductor ◽  
Lattice Contribution ◽  
Electronic Transport Properties ◽  
P Type

The encapsulated induction melting was attempted to prepare the Sn-filled CoSb3 skutterudites and their electronic transport properties were investigated. Single phase δ-CoSb3 was successfully obtained by the subsequent isothermal heat treatment at 823K for 6 days in vacuum. The Sn-filled CoSb3 showed p-type conductivity at 300K to 700K at it is a highly degenerate semiconductor. Lattice contribution was dominant to thermal conductivity and it was considerably reduced by Sn filling in the CoSb3 skutterudite.

Microstructure, magnetic and electronic transport properties of reactively facing-target sputtered epitaxial Mn4N films

2021 ◽  
Author(s):  
Zeyu Zhang ◽  
Xiaohui Shi ◽  
Xiang Liu ◽  
Xia Chen ◽  
Wenbo Mi
Keyword(s):  
Transport Properties ◽  
Electronic Transport ◽  
Perpendicular Magnetic Anisotropy ◽  
Wave Theory ◽  
Residual Resistivity ◽  
Electronic Transport Properties ◽  
Crystal Field Effect ◽  
Transmission Electron ◽  
Pole Figures ◽  
Increasing Temperature

Abstract The structure, magnetic and electronic transport properties of epitaxial Mn4N films fabricated by the facing-target reactive sputtering method have been investigated systematically. The high-quality growth of Mn4N films was confirmed by X-ray θ-2θ, pole figures and high-resolution transmission electron microscopy. The Mn4N films exhibit ferrimagnetic with strong perpendicular magnetic anisotropy. The saturation magnetization of Mn4N films decreases with increasing temperature, following the Bloch’s spin wave theory. The resistivity of Mn4N films exhibits metallic conductance mechanism. Debye temperature of Mn4N is estimated to be 85 K. The calculated residual resistivity ρxx0 of the 78.8 nm-thick Mn4N film is 30.56 μΩ cm. The magnetoresistances of Mn4N films display a negative signal and butterfly shape. The sign of anisotropic magnetoresistance (AMR) is positive, which infers that the AMR is dominated by the spin-up conduction electrons. Moreover, the transformation of fourfold to twofold symmetry for AMR and twofold to onefold symmetry for planar Hall resistivity is attributed to tetragonal crystal field effect.

scholarly journals Structure, electrical conductivity and oxygen transport properties of Ruddlesden–Popper phases Lnn+1NinO3n+1 (Ln = La, Pr and Nd; n = 1, 2 and 3)

2020 ◽  
Vol 8 (42) ◽  
pp. 22206-22221
Author(s):  
Jia Song ◽  
De Ning ◽  
Bernard Boukamp ◽  
Jean-Marc Bassat ◽  
Henny J. M. Bouwmeester
Keyword(s):  
Electrical Conductivity ◽  
Transport Properties ◽  
Oxygen Transport ◽  
Electronic Transport ◽  
Layered Structure ◽  
Electronic Transport Properties ◽  
Oxygen Ion

Correlating oxygen-ion and electronic transport properties of Ruddlesden–Popper-type nickelates with their layered structure.

scholarly journals Charge Transport and Thermoelectric Properties of Mn-Doped Tetrahedrites Cu12-xMnxSb4S13

2021 ◽  
Vol 59 (5) ◽  
pp. 329-335
Author(s):  
Sung-Yoon Kim ◽  
Go-Eun Lee ◽  
Il-Ho Kim
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Lattice Constant ◽  
Figure Of Merit ◽  
Phase Changes ◽  
Total Thermal Conductivity ◽  
Mn Content ◽  
Increasing Temperature ◽  
P Type ◽  
Mn Doped

Mn-doped tetrahedrites Cu12-xMnxSb4S13 (0.1 ≤ x ≤ 0.4) were synthesized by mechanical alloying (MA) and sintered by hot pressing (HP). A single tetrahedrite phase was synthesized by MA without post-annealing, and it was stable without any phase changes after HP. The hot-pressed specimens had a relative density higher than 98.6%. The lattice constant of the Mn-doped samples increased compared to that of undoped Cu12Sb4S13, but no significant change in the lattice constant was observed with a change in Mn content. All Mn-doped tetrahedrites acted as p-type semiconductors, as confirmed from positive Hall and Seebeck coefficient values. The Seebeck coefficient increased with increasing temperature but decreased with increasing Mn content; maximum Seebeck coefficient values of 200−219 μVK-1 were obtained at 323−723 K for x = 0.1. Electrical conductivity increased with increasing temperature and Mn content; the highest electrical conductivity values of (1.76−2.45) × 104 Sm-1 were obtained at 323−723 K for x = 0.4. As a result, Cu11.6Mn0.4Sb4S13 exhibited a maximum power factor of 0.80 mWm-1K-2 at 723 K. As the Mn content increased, both the electronic and lattice thermal conductivities increased, and thus, the total thermal conductivity was the lowest at 0.48–0.63Wm-1K-1 at 323–723 K for x = 0.1. A maximum dimensionless figure of merit of 0.75 was obtained at 723 K for Cu11.7Mn0.3Sb4S13. The MA-HP process is suitable for preparing doped tetrahedrites exhibiting excellent thermoelectric performance.

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